This invention relates to a method for the combustive treatment of a waste fluid, such as an exhaust gas or spent liquor, which contains compounds generating nitrogren oxides upon combustion in the presence of air.
Large amounts of nitrogen oxides, the NO.sub.x, are produced when burning waste materials containing nitrogen compounds, causing a problem of environmental pollution. Especially, when the nitrogen compounds have no nitrogen-hydrogen bonds such as nitro, nitroso, nitrate, cyan, isocyanate and cyanate compounds, they are easily decomposed or oxidized within wide ranges of temperature and oxygen concentrations to generate nitrogen oxides. In view of preventing air pollution which has now become a big social problem, therefore, it is highly desirable to inhibit discharge of nitrogen oxides from combustion units.
In the combustive treatment of waste materials, the use of a compact combustion furnace is desirable to avoid a requirement for large floor space and to save construction costs. In compact furnaces, however, in order to ensure complete combustion of combustible materials in the waste material and to enable high-load combustion, it is necessary to effect the combustion at a temperature of at least 1200.degree. C. Such high temperature combustion necessarily invites production of nitrogen oxides in increased amounts.